{"id":"CVE-2021-32714","aliases":["DEBIAN-CVE-2021-32714","EUVD-2021-1440","GHSA-5h46-h7hh-c6x9","RUSTSEC-2021-0079","UBUNTU-CVE-2021-32714","openSUSE-SU-2024:11751-1"],"status":"published","title":"Integer Overflow in Chunked Transfer-Encoding","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.01155,"percentile":0.67431,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-190"],"published":"2021-07-07T12:00:00Z","modified":"2026-10-23T18:03:14Z","fixes":[{"ecosystem":"crates.io","package":"hyper","fixed_in":["0.14.10"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:12","package":"rust-hyper","fixed_in":["0.14.19-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"rust-hyper","fixed_in":["0.14.19-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"rust-hyper","fixed_in":["0.14.19-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"hyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.14.10"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"rust-hyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.14.19-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"rust-hyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.14.19-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"rust-hyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.14.19-1"}]}]},{"source":"osv","ecosystem":"crates.io","package":"hyper","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.14.10"}]}]},{"source":"osv","ecosystem":"crates.io","package":"hyper","ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.14.10"}]}]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"rust-hyper","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.12.35-1"]}],"products":[{"vendor":"hyper","product":"hyper"},{"vendor":"hyperium","product":"hyper"},{"vendor":"vercel","product":"hyper"}],"references":[{"url":"https://github.com/hyperium/hyper/security/advisories/GHSA-5h46-h7hh-c6x9","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Third Party Advisory","evidence","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32714","tags":["advisory"]},{"url":"https://rustsec.org/advisories/RUSTSEC-2021-0079.html","tags":["web","advisory","report"]},{"url":"https://github.com/advisories/GHSA-5h46-h7hh-c6x9"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-32714","tags":["advisory"]},{"url":"https://github.com/hyperium/hyper","tags":["package"]},{"url":"https://crates.io/crates/hyper","tags":["package"]},{"url":"https://github.com/hyperium/hyper/commit/efd9a9821fd2f1ae04b545094de76a435b62e70f","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2021-32714","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-32714","tags":["report"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2020-35905","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-36465","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-27378","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-32714","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-32715","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-38191","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2021-45710","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2021-32714","title":"Integer Overflow in Chunked Transfer-Encoding","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","status":"published","published":"2021-07-07T19:35:10Z","modified":"2024-08-03T23:25:31.083Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-190"],"updated_at":"2026-11-02T14:33:07.014772Z"}],"euvd":[{"id":"EUVD-2021-1440","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","status":"published","published":"2021-07-07T19:35:10Z","modified":"2024-08-03T23:25:31Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T03:24:36.41075Z"}],"ghsa":[{"id":"GHSA-5h46-h7hh-c6x9","title":"Integer Overflow in Chunked Transfer-Encoding","description":"### Summary\n\nhyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks\".\n\n### Vulnerability\n\nExample:\n\n```\nGET / HTTP/1.1\nHost: example.com\nTransfer-Encoding: chunked\n\nf0000000000000003\nabc\n0\n\n```\n\nhyper only reads the rightmost 64-bit integer as the chunk size. So it reads `f0000000000000003` as `3`. A loss of data can occur since hyper would then read only 3 bytes of the body. Additionally, an HTTP request smuggling vulnerability would occur if using a proxy which instead has prefix truncation in the chunk size, or that understands larger than 64-bit chunk sizes.\n\nRead more about desync attacks: https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn\n\n### Impact\n\nTo determine if vulnerable to _data loss_, these things must be true:\n\n- **Using HTTP/1.1.** Since HTTP/2 does not use chunked encoding, it is not vulnerable.\n- **Using hyper as a server or client.** The body would be improperly truncated in either case.\n- **Users send requests or responses with chunk sizes greater than 18 exabytes**.\n\nTo determine if vulnerable to _desync attacks_, these things must be true:\n\n- **Using an upstream proxy that allows chunks sizes larger than 64-bit.** If the proxy rejects chunk sizes that are too large, that request won't be forwarded to hyper.\n\n### Patches\n\nWe have released the following patch versions:\n\n - v0.14.10 (to be released when this advisory is published)\n\n### Workarounds\n\nBesides upgrading hyper, you can take the following options:\n\n- Reject requests manually that contain a `Transfer-Encoding` header.\n- Ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.\n\n\n### Credits\nThis issue was initially reported by [Mattias Grenfeldt](https://grenfeldt.dev/) and Asta Olofsson.","status":"published","published":"2021-07-12T16:55:37Z","modified":"2023-02-03T05:06:14Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-190"],"updated_at":"2026-11-02T14:36:43.439065Z"}],"nvd":[{"id":"CVE-2021-32714","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","status":"published","published":"2021-07-07T20:15:08.65Z","modified":"2026-06-17T03:53:28.94Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":6.4,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-190"],"updated_at":"2026-11-02T14:06:55.259633Z"}],"osv":[{"id":"CVE-2021-32714","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","status":"published","published":"2021-07-07T20:15:08.65Z","modified":"2026-10-20T10:54:42.597143978Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:44:19.793849Z"},{"id":"DEBIAN-CVE-2021-32714","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","status":"published","published":"2021-07-07T20:15:08.65Z","modified":"2026-10-23T18:03:14.557211398Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:45:35.233346Z"},{"id":"GHSA-5h46-h7hh-c6x9","title":"Integer Overflow in Chunked Transfer-Encoding","description":"### Summary\n\nhyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks\".\n\n### Vulnerability\n\nExample:\n\n```\nGET / HTTP/1.1\nHost: example.com\nTransfer-Encoding: chunked\n\nf0000000000000003\nabc\n0\n\n```\n\nhyper only reads the rightmost 64-bit integer as the chunk size. So it reads `f0000000000000003` as `3`. A loss of data can occur since hyper would then read only 3 bytes of the body. Additionally, an HTTP request smuggling vulnerability would occur if using a proxy which instead has prefix truncation in the chunk size, or that understands larger than 64-bit chunk sizes.\n\nRead more about desync attacks: https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn\n\n### Impact\n\nTo determine if vulnerable to _data loss_, these things must be true:\n\n- **Using HTTP/1.1.** Since HTTP/2 does not use chunked encoding, it is not vulnerable.\n- **Using hyper as a server or client.** The body would be improperly truncated in either case.\n- **Users send requests or responses with chunk sizes greater than 18 exabytes**.\n\nTo determine if vulnerable to _desync attacks_, these things must be true:\n\n- **Using an upstream proxy that allows chunks sizes larger than 64-bit.** If the proxy rejects chunk sizes that are too large, that request won't be forwarded to hyper.\n\n### Patches\n\nWe have released the following patch versions:\n\n - v0.14.10 (to be released when this advisory is published)\n\n### Workarounds\n\nBesides upgrading hyper, you can take the following options:\n\n- Reject requests manually that contain a `Transfer-Encoding` header.\n- Ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.\n\n\n### Credits\nThis issue was initially reported by [Mattias Grenfeldt](https://grenfeldt.dev/) and Asta Olofsson.","status":"published","published":"2021-07-12T16:55:37Z","modified":"2026-09-10T03:49:06.30595906Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-190"],"updated_at":"2026-11-02T15:46:38.553953Z"},{"id":"RUSTSEC-2021-0079","title":"Integer overflow in `hyper`'s parsing of the `Transfer-Encoding` header leads to data loss","description":"When decoding chunk sizes that are too large, `hyper`'s code would encounter an integer overflow. Depending on the situation,\nthis could lead to data loss from an incorrect total size, or in rarer cases, a request smuggling attack.\n\nTo be vulnerable, you must be using `hyper` for any HTTP/1 purpose, including as a client or server, and consumers must send\nrequests or responses that specify a chunk size greater than 18 exabytes. For a possible request smuggling attack to be possible,\nany upstream proxies must accept a chunk size greater than 64 bits.","status":"published","published":"2021-07-07T12:00:00Z","modified":"2026-10-12T18:00:02.671544457Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:53:39.492624Z"},{"id":"UBUNTU-CVE-2021-32714","description":"hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in \"request smuggling\" or \"desync attacks.\" The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a `Transfer-Encoding` header or ensure any upstream proxy rejects `Transfer-Encoding` chunk sizes greater than what fits in 64-bit unsigned integers.","status":"published","published":"2021-07-07T20:15:00Z","modified":"2025-10-24T04:50:20Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:54:27.332852Z"},{"id":"openSUSE-SU-2024:11751-1","title":"afterburn-5.0.0-6.1 on GA media","description":"These are all security issues fixed in the afterburn-5.0.0-6.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T03:42:02.541488Z","updated_at":"2026-11-02T16:58:35.195147Z"}]}}